< draft-ietf-bfd-multipoint-active-tail-06.txt		draft-ietf-bfd-multipoint-active-tail-07.txt >
	Internet Engineering Task Force D. Katz		Internet Engineering Task Force D. Katz
	Internet-Draft Juniper Networks		Internet-Draft Juniper Networks
	Intended status: Standards Track D. Ward		Intended status: Standards Track D. Ward
	Expires: June 22, 2018 Cisco Systems		Expires: July 19, 2018 Cisco Systems
	S. Pallagatti, Ed.		S. Pallagatti, Ed.
	Individual Contributor		Individual Contributor
	G. Mirsky, Ed.		G. Mirsky, Ed.
	ZTE Corp.		ZTE Corp.
	December 19, 2017		January 15, 2018
	BFD Multipoint Active Tails.		BFD Multipoint Active Tails.
	draft-ietf-bfd-multipoint-active-tail-06		draft-ietf-bfd-multipoint-active-tail-07
	Abstract		Abstract
	This document describes active tail extensions to the Bidirectional		This document describes active tail extensions to the Bidirectional
	Forwarding Detection (BFD) protocol for multipoint and multicast		Forwarding Detection (BFD) protocol for multipoint and multicast
	networks.		networks.
	Requirements Language		Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	skipping to change at page 1, line 45 ¶		skipping to change at page 1, line 45 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on June 22, 2018.		This Internet-Draft will expire on July 19, 2018.
	Copyright Notice		Copyright Notice
	Copyright (c) 2017 IETF Trust and the persons identified as the		Copyright (c) 2018 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	skipping to change at page 2, line 29 ¶		skipping to change at page 2, line 29 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 4		3. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 4
	3.1. Multipoint Client Session . . . . . . . . . . . . . . . . 4		3.1. Multipoint Client Session . . . . . . . . . . . . . . . . 4
	3.2. Multipoint Client Session Failure . . . . . . . . . . . . 5		3.2. Multipoint Client Session Failure . . . . . . . . . . . . 5
	3.3. State Variables . . . . . . . . . . . . . . . . . . . . . 5		3.3. State Variables . . . . . . . . . . . . . . . . . . . . . 5
	3.3.1. New State Variables . . . . . . . . . . . . . . . . . 5		3.3.1. New State Variables . . . . . . . . . . . . . . . . . 5
	3.3.2. State Variable Initialization and Maintenance . . . . 6		3.3.2. New State Variable Value . . . . . . . . . . . . . . 6
			3.3.3. State Variable Initialization and Maintenance . . . . 6
	3.4. Controlling Multipoint BFD Options . . . . . . . . . . . 7		3.4. Controlling Multipoint BFD Options . . . . . . . . . . . 7
	3.5. State Machine . . . . . . . . . . . . . . . . . . . . . . 8		3.5. State Machine . . . . . . . . . . . . . . . . . . . . . . 8
	3.6. Session Establishment . . . . . . . . . . . . . . . . . . 8		3.6. Session Establishment . . . . . . . . . . . . . . . . . . 8
	3.7. Discriminators and Packet Demultiplexing . . . . . . . . 8		3.7. Discriminators and Packet Demultiplexing . . . . . . . . 8
	3.8. Controlling Tail Packet Transmission . . . . . . . . . . 8		3.8. Controlling Tail Packet Transmission . . . . . . . . . . 8
	3.9. Soliciting the Tails . . . . . . . . . . . . . . . . . . 9		3.9. Soliciting the Tails . . . . . . . . . . . . . . . . . . 9
	3.10. Verifying Connectivity to Specific Tails . . . . . . . . 9		3.10. Verifying Connectivity to Specific Tails . . . . . . . . 10
	3.11. Detection Times . . . . . . . . . . . . . . . . . . . . . 10		3.11. Detection Times . . . . . . . . . . . . . . . . . . . . . 10
	3.12. MultipointClient Down/AdminDown Sessions . . . . . . . . 11		3.12. MultipointClient Down/AdminDown Sessions . . . . . . . . 11
	3.13. Base BFD Specification Text Replacement . . . . . . . . . 11		3.13. Base BFD Specification Text Replacement . . . . . . . . . 11
	3.13.1. Reception of BFD Control Packets . . . . . . . . . . 11		3.13.1. Reception of BFD Control Packets . . . . . . . . . . 11
	3.13.2. Demultiplexing BFD Control Packets . . . . . . . . . 12		3.13.2. Demultiplexing BFD Control Packets . . . . . . . . . 12
	3.13.3. Transmitting BFD Control Packets . . . . . . . . . . 12		3.13.3. Transmitting BFD Control Packets . . . . . . . . . . 12
	4. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 13		4. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 13
	5. Operational Scenarios . . . . . . . . . . . . . . . . . . . . 13		5. Operational Scenarios . . . . . . . . . . . . . . . . . . . . 14
	5.1. No Head Notification . . . . . . . . . . . . . . . . . . 14		5.1. No Head Notification . . . . . . . . . . . . . . . . . . 14
	5.2. Unreliable Head Notification . . . . . . . . . . . . . . 14		5.2. Unreliable Head Notification . . . . . . . . . . . . . . 14
	5.3. Semi-reliable Head Notification and Tail Solicitation . . 14		5.3. Semi-reliable Head Notification and Tail Solicitation . . 14
	5.4. Reliable Head Notification . . . . . . . . . . . . . . . 15		5.4. Reliable Head Notification . . . . . . . . . . . . . . . 15
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 16		7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
	8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 16		8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 16
	9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16		9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
	10. Normative References . . . . . . . . . . . . . . . . . . . . 16		10. Normative References . . . . . . . . . . . . . . . . . . . . 16
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
	skipping to change at page 5, line 23 ¶		skipping to change at page 5, line 23 ¶
	know the tail state.		know the tail state.
	3.3. State Variables		3.3. State Variables
	BFD Multipoint active tail introduces new state variables and		BFD Multipoint active tail introduces new state variables and
	modifies the usage of a few existing ones defined in section 4.4 of		modifies the usage of a few existing ones defined in section 4.4 of
	[I-D.ietf-bfd-multipoint].		[I-D.ietf-bfd-multipoint].
	3.3.1. New State Variables		3.3.1. New State Variables
	Few state variables are added and modified support of Multipoint BFD		Few state variables are added in support of Multipoint BFD active
	active tail.		tail.
	bfd.SessionType
	The type of this session as defined in [RFC7880]. A new value
	introduced is:
	MultipointClient: A session on the head that tracks the
	state of an individual tail, when desirable.
	This variable MUST be initialized to the appropriate type when
	the session is created, according to the rules in section 4.13
	of [I-D.ietf-bfd-multipoint].
	bfd.SilentTail		bfd.SilentTail
	If 0, a tail may send packets to the head according to other		If 0, a tail may send packets to the head according to other
	parts of this specification. Setting this to 1 allows tails to		parts of this specification. Setting this to 1 allows tails to
	be provisioned to always be silent, even when the head is		be provisioned to always be silent, even when the head is
	soliciting traffic from the tails. This can be useful, for		soliciting traffic from the tails. This can be useful, for
	example, in deployments of a large number of tails when the		example, in deployments of a large number of tails when the
	head wishes to track the state of a subset of them. This		head wishes to track the state of a subset of them. This
	variable MUST be initialized based on configuration.		variable MUST be initialized based on configuration.
	skipping to change at page 6, line 15 ¶		skipping to change at page 6, line 4 ¶
	periodic BFD Control packets, when they see the BFD session		periodic BFD Control packets, when they see the BFD session
	fail. If 0, the tail will never send periodic BFD Control		fail. If 0, the tail will never send periodic BFD Control
	packets, and the head will not be notified of session failures		packets, and the head will not be notified of session failures
	by the tails. This variable MUST be initialized based on		by the tails. This variable MUST be initialized based on
	configuration.		configuration.
	This variable is only pertinent when bfd.SessionType is		This variable is only pertinent when bfd.SessionType is
	MultipointHead or MultipointClient.		MultipointHead or MultipointClient.
	bfd.UnicastRcvd		bfd.UnicastRcvd
	Set to 1 if a tail receives a unicast BFD Control packet from		Set to 1 if a tail receives a unicast BFD Control packet from
	the head. This variable MUST be set to zero if the session		the head. This variable MUST be set to zero if the session
	transitions from Up state to some other state.		transitions from Up state to some other state.
	This variable MUST be initialized to zero.		This variable MUST be initialized to zero.
	This variable is only pertinent when Bfd.SessionType is		This variable is only pertinent when Bfd.SessionType is
	MultipointTail.		MultipointTail.
	3.3.2. State Variable Initialization and Maintenance		3.3.2. New State Variable Value
			A new state variable value being added to:
			bfd.SessionType
			The type of this session as defined in [RFC7880]. A new value
			introduced is:
			MultipointClient: A session on the head that tracks the state
			of an individual tail, when desirable.
			This variable MUST be initialized to the appropriate type when the
			session is created, according to the rules in section 4.13 of
			[I-D.ietf-bfd-multipoint].
			3.3.3. State Variable Initialization and Maintenance
	Some state variables defined in section 6.8.1 of the [RFC5880] needs		Some state variables defined in section 6.8.1 of the [RFC5880] needs
	to be initialized or manipulated differently depending on the session		to be initialized or manipulated differently depending on the session
	type (see section 4.4.2 of [I-D.ietf-bfd-multipoint]).		type (see section 4.4.2 of [I-D.ietf-bfd-multipoint]).
	bfd.LocalDiscr		bfd.LocalDiscr
	For session type MultipointClient, this variable MUST always		For session type MultipointClient, this variable MUST always
	match the value of bfd.LocalDiscr in the associated		match the value of bfd.LocalDiscr in the associated
	MultipointHead session.		MultipointHead session.
	skipping to change at page 16, line 30 ¶		skipping to change at page 16, line 37 ¶
	9. Acknowledgements		9. Acknowledgements
	Authors would also like to thank Nobo Akiya, Vengada Prasad Govindan,		Authors would also like to thank Nobo Akiya, Vengada Prasad Govindan,
	Jeff Haas, Wim Henderickx, Gregory Mirsky and Mingui Zhang who have		Jeff Haas, Wim Henderickx, Gregory Mirsky and Mingui Zhang who have
	greatly contributed to this document.		greatly contributed to this document.
	10. Normative References		10. Normative References
	[I-D.ietf-bfd-multipoint]		[I-D.ietf-bfd-multipoint]
	Katz, D., Ward, D., and J. Networks, "BFD for Multipoint		Katz, D., Ward, D., Networks, J., and G. Mirsky, "BFD for
	Networks", draft-ietf-bfd-multipoint-11 (work in		Multipoint Networks", draft-ietf-bfd-multipoint-12 (work
	progress), December 2017.		in progress), December 2017.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection		[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
	(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,		(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
	<https://www.rfc-editor.org/info/rfc5880>.		<https://www.rfc-editor.org/info/rfc5880>.
End of changes. 12 change blocks.
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